COMPUTATIONAL MODELLING OF COMPOSITE STRUCTURES UNDER LOW-VELOCITY IMPACT

Abstract

In this thesis, a general numerical method to solve the transient response of laminated composite beams, plates and shells subjected to the low-velocity impact of a mass is developed for various boundary conditions and stacking sequences. Unlike the traditional integral equation method, the impactor and the impacted structure are considered as a system. The equations of motion are derived by applying the higher order shear deformation theory, the Lagrange's Principle and the Hertz contact law. The governing equations can be easily solved by employing computational techniques. Accurate solutions can be obtained based on the proposed method. In this method, a set of simple polynomial series is proposed to approximate to the generalised mid-plane displacements for various boundary conditions. The principal transformation method is then introduced to decouple the second terms in the equations of motion. The resulting decoupled equations of motion are finally solved by employing the Runge-Kutta-Nystron method. The method is also extended to analyse the dynamic responses of the laminated plates and shells subjected to explosive type loading. The decoupled governing equations in terms of principal co-ordinates are solved analytically by applying the convolution integral. Numerical results obtained by the present method are compared with those published in the literature, and very good agreements are achieved. The effects of edge condition, fibre orientation on the dynamic response for low-velocity impact are fully discussed for the laminated composite beams, plates and shells.